Hello all, I have a question to pose to all the experienced people here. I went out to shoot a few images last night and to just play around with my D90 at night. I noticed a lot of noise in the shots and am wondering what may be causing it. The images were shot at 200 ISO, f11 with a shutter speed of 25 seconds. Now for my question. When using a slow shutter speed at 200 ISO, is there an expectation that the noise will increase in the image due to the length of exposure? I tried pumping up the ISO 640 and decreasing the shutter speed, noticed a slight decrease in the noise, but not by much.